duel fuel tanks

[lujo]

Rear fuel tank shows half a tank but will stall if switch is left on rear tank. Sitting at a light the other day the van began to sputter . I started pumping the pedal and it fought to stay running. As soon as I switched over to the front tank it was fine. any ideas?
Thanks in advance

[iselinzilla]

Dual tanks have a low pressure fuel pump in each tank. There are a couple of things that can go wrong.

If fuel was left sitting in the tank for a long time it may deteriorate into varnish and a flap of this may plug the intake screen.

The fuel pump in the tank may be weak, letting only partial fuel through. This isn't probable though. In my experience, either the pump pumps or it doesn't.

There may be a hole in the intake hose before the fuel reaches the pump, allowing it to suck air. I've seen this happen even on newer vans.

Good luck.